Like stroke, a transient ischemic attack (TIA) is caused by restricted blood supply to the brain. Symptoms may last only a few minutes.

"All patients should get a CT scan of their brain after a TIA or non-disabling stroke," said the study's co-senior author Jeffrey Perry, an associate professor of emergency medicine at the University of Ottawa in Canada.

"Images can help healthcare professionals identify patterns of damage associated with different levels of risk for a subsequent stroke or help predict when symptoms may get worse," Perry added.

For the study, the researchers tracked more than 2,028 patients who received CT scans within 24 hours of a TIA. The scans revealed that 40 percent of them had brain damage due to impaired circulation (ischemia).

Compared to patients without ischemia, the probability of another stroke occurring within 90 days of the initial episode was 2.6 times greater if the CT image revealed newly damaged tissue due to poor circulation (acute ischemia).

The researchers found that higher the damage to the brain, greater was the risk of another stroke within 90 days, making the scans a useful prediction tool.